I’m horrible with geography but here’s an unprotected mango growing in Pittsburg California
https://m.youtube.com/watch?v=LXoSQQkjLHsProbably have to do your homework and plant in the warmest microclimate and having nice, huge dark boulders for thermal mass will help.
If you try, definitely start with seedlings and not grafted trees.
Research has shown that it is the size of the tree that correlates with cold tolerance. The larger the tree, the better your chance of survival.
Maybe start with multiple seedlings in root pruning pots and keep them in pots until they are as large as you can manage dragging into the garage or other warm protected place in the winter.
Once it grows to an unmanageable size, plant it into the ground after last chance of frost.
If you keep up potting into the next size up root pruning pot, your tree should have a nice healthy root system.
Take into consideration that the root mass is approximately equal to the above ground mass of branches. Down in the earth, the temperatures are much more stable than above ground due to the thermal mass of the earth and the specific heat of earth vs air.
If you get a once in 20 year cold event however, it could still kill your tree if unprotected. For a single tree, you can use a patio heater.
Simon